Fuel injection control system

ABSTRACT

A hydraulic fuel injection control system for internal combustion gas engines which includes means at the valve end of the system for precisely adjusting the volume of the charge injected. In a two cylinder engine, the adjustment means is included on at least one injector valve in order to balance the size of the injected charges in the two cylinders. The adjustment means includes an external cylindrical adjustment sleeve threadably attached to the valve assembly adjacent the end of a valve plunger which operates the valve. About the plunger and connected to the adjustment sleeve is a slave cylinder through which the pressurized hydraulic fluid is received from a cam driven pump. The cylinder includes oil return spillports in communication with the valve plunger, the ports being axially movable with respect to the plunger by rotation of the collar upon screw threads. Axial movement of the ports effects an adjustment of the size of the charge by varying the point at which the plunger opens the spillports to relieve the hydraulic fluid pressure.

United States Patent Gates 1 [111 3,872,844 1 Mar. 25, 1 9 75 1 1 FUELINJECTION CONTROL SYSTEM [75] Inventor: Alfred C. Gates, Corry, Pa.

[73] Assignee: Cooper Industries Inc., Houston,

Tex.

[22] Filed: Nov. 12, 1973 [21] Appl. No.: 414,884

[56] References Cited UNITED STATES PATENTS 2,602,434 7/1952 Barnaby123/9012 3,003,471 10/1961 Bodem ct 211.... 91/402 X 3,402.913 9/1968Payne ct a1.

Primary E.\aminerCharles J. Myhre Assistant Examiner-Tony ArgenbrightAttorney, Agent, or Firm-Owen & Owen [57] ABSTRACT A hydraulic fuelinjection control system for internal combustion gas engines whichincludes means at the valve end of the system for precisely adjustingthe volume of the charge injected. In a two cylinder engine, theadjustment means is included on at least one injector valve in order tobalance the size of the injected charges in the two cylinders. Theadjustment means includes an external cylindrical adjustment sleevethreadably attached to the valve assembly adjacent the end of a valveplunger which operates the valve. About the plunger and connected to theadjustment sleeve is a slave cylinder through which the pressurizedhydraulic fluid is received from a cam driven pump. The cylinderincludes oil return spillports in communication with the valve plunger,the ports being axially movable with respect to the plunger by rotationof the collar upon screw threads. Axial movement of the ports effects anadjustment of the size of the charge by varying the point at which theplunger opens the spillports to relieve the hydraulic fluid pressure.

10 Claims, 5 Drawing Figures PATENTED HARE 5 I975 snans'org FUELINJECTION CONTROL SYSTEM BACKGROUND OF THE INVENTION The inventionrelates to hydraulically operated fuel injection systems, and moreparticularly to fuel metering control means for'such systems instationary gas engines used for gas transmission, power generation andanalogous uses.

Hydraulic valve and pump operating mechanisms are well known. Ingeneral,.a cam driven hydraulic pump applies a series of timed andmetered charges of hydraulic fluid to a fuel valve in the enginecylinder, with the time and duration of the opening of the fuel valvesolely dependent upon the hydraulic charges or signals derived from thepump. A spillport system wherein valve lift duration is controlled bythe position of a hydraulic fluid spillport in the pump plunger cylinderor the valve plunger cylinder or both is disclosed in U.S. Pat. No.2,602,434. In this system, there is a means for varying the duration andtiming of the valve lift by rotational adjustment of the plungers atboth pump and valve by a manual adjustment ring which turns the plungersto vary their inclined end facerelative to a spillport.

In diesel fuel injection systems, particularly those employing a plungerpump which directly injects the fuel, means foraxially varying the pointat which fuel pressure in the pump is released to terminate an injectionstroke are known. See U.S. Pat. Nos. 2,225,019, 2,813,523, and3,673,996.

Prior art systems, however, have not provided a simplified, effectivemeans for adjusting the volume of the fuel charge directly at the valve,where adjustment can be most responsive and accurate. The poppet valveadjustable hydraulic system disclosed in the above mentioned U.S. Pat.No. 2,602,434 involves the use of two adjustments, one at each end ofthe system. Particularly in multiple cylinder gas engines, there is needfor a fuel control system having a simple, effective, easily operatedcharge size adjustment at the valve end of the cylinders in order tobalance the charges in the two cylinders for balanced combustion. Theprior art has not provided such a control system.

SUMMARY THEINVENTION The present invention provides a fuel feed controlsystem particularly useful in two cylinder fluid fuel engines such asnatural gas but is also applicable to other forms of internal combustionengines. The hydraulically operated system employs a cam operatedplunger pump which feeds fluid to a fluid chamber and a slave cylinderoperating the plunger of a spring returnablevalve. Pressurized fuel isadmitted through a duct adjacent the valve head. Radially disposedspillports in the slave cylinder wallsare provided to vent the systemthrough an oil return line when the plunger end clears cluding thespillports, so that when the adjustment sleeve is rotated, the point atwhich relief venting of the system occurs is altered, providing therequired charge size adjustment.

The present system further provides a finely adjustable system which iseasily operated. The radially disposed spillports communicating with theplunger and slave cylinder are rectangular rather than circular incross-section, so that the effective length of the plunger stroke changelinearly with rotation of the adjustment sleeve, which would not be thecase with circular spillports. This facilitates finer and easieradjustment of the system, particularly in the context of a two cylindergas engine in which the charge of one cylinder must be balanced with thecharge of the other for balanced load conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective viewof a fuel injection control system according to the present invention,shown in connection with a pair of combustion cylinders;

FIG. 2 is a cross-sectional view in elevation of a valve assemblyincluding adjustment means according to the invention;

FIG. 3 is an enlarged sectional view taken along the line 33. of FIG. 2;

FIG. 4 is an enlarged perspective view of a slave cylinder barrel shownremoved from the assembly of FIG. 2; and

FIG. 5 is an enlarged cross-sectional view of the valve assembly takenalong the line 55 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT A fuel control system accordingto the invention is shown in FIG. 1 generally indicated by the referencenumber 10. The system 10 is operably connected to combustion cylinders11 and'12, diagrammatically indicated as part of a two cylinder gasinternal combustion engine. The hydraulicsystem 10 includes an oilreservoir tank 13 coupled by a hydraulic supply line 14 to the intakesofa pair of cam-operated plunger pumps 15 and 16. Cams 15c and 16c aredriven by the engine of which the cylinders 11 and 12 are a part.Hydraulic supply lines 17 and 18 carry pressurized oil from the pumps 15and 16 through a line support 19 to valve assemblies 21 and 22 connectedinto the heads of the combustion cylinders 11 and 12,. respectively. Oilreturn lines 23 and 24 return the hydraulic fluid from the valveassemblies 21 and 22 through the line support 19 to the fluid tank 13.Also connected to the oil reservoir tank 13 is a valved pressure line 25communicating, through a fuel supply line 28, with a pressurized sourceof gaseous fuel (not shown). Manifold fuel pressure is thus exerted onthe surface of the hydraulic fluid in the tank 13 to maintain the fluidin the system 10 under pressure. The tank 13, pumps 15 and 16, valveassemblies 21 and 22, and the various fluid lines 17, 18, 23, and 24make up a closed hydraulic system.

The fuel supply line 28 transmits fuel from the pressurized source to apair of fuel conduits 29 and 30 which terminate in connection to thevalve assemblies 21 and 22, respectively.

Referring now to FIGS. 2-5, the valve assembly 22 is shown in anenlarged cross-sectional view. A valve 33 including a valve head 34 andvalve seat 35 is posiis admitted to a chamber 36 adjacent the valve 33through the fuel conduit and will thus be admitted to the cylinder 12under its own manifold pressure when the valve 33 is open, as it isshown in broken line position in FIG. 2. The valve assembly 22 includesa lower housing 37 connected to an upper housing 38 through which avalve stem 39 connected to the valve head 34 reciprocates. A compressionspring 40 disposed between the lower housing 37 and a collar 43 on thevalve stem 39 provides a biased closing force for the valve head 34. Thevalve stem 39 is slidable through a valve guide 44 which is rigidlymounted within the lower housing 37. A valve stem lubrication fitting 45and line 46 are provided.

In this description and in the following claims; the expressions upward,downward, upper, lower, etc., characterize the valve assemblyorientation as seen in FIGS. 2 and 5, with the understanding that thevalve assembly can be installed in any orientation.

Threadably connected to the upper end of the upper housing 38 is anexternal adjustment sleeve 48. The sleeve 48 includes an upper collar 49which retains a cap 50 by engaging a lower flange 51 thereon. The sleeve48 rotates on its threads with respect to the cap 50 and the upperhousing 38. A cylindrical barrel 52 having an upper flange 53 (shown indetail in FIG. 4) is mounted to the lower end of the cap 50 and retainedthere by means of a mounting sleeve 54 which is connected to the cap 50preferably by means of bolts 55. This construction is best seen in FIG.5. Guide pins 56 prevent the sleeve 54 from rotating with respect to theupper housing 38. To bias the sleeve 54, cap 50 and barrel 52 upwardagainst the collar 49 of the external adjustment sleeve 48, compressionsprings 57 are mounted within recesses 58 and 59 in the sleeve 54 and rthe upper housing 38, respectively. O-rings 60 and 61 provide sealsbetween the cap 50 and the barrel 52. Another O-ring 61a provides a sealbetween the lower end of the barrel 52 and the upper housing 38. Ahydraulic elastomeric seal 61b is provided within the barrel 52 againstthe plunger 62.

Mounted for slidable reciprocation within the barrel 52 is a valveplunger 62, the lower end 63 of which abuts the upper end of the valvestem 39. A compression spring 64 extending between the top end of theplunger 62 and a seat 65 in the cap 50 maintains the plunger 62 andvalve stem 39 in abutting relationship.

The compression spring 64 resides in enclosed fluid chamber 66 incommunication with the oil supply line 18 from the pump 16. The plunger62 acts as a piston within a slave cylinder 67 defined by the barrel 52just below the chamber 66, so that as the hydraulic pump 16 forces oilthrough the line 18 into the chamber 66, the plunger 62, valve stem 39,and valve head 34 are moved downward against the compression spring 40to open the valve 33. Thus the time for initial opening of the valve 33is set by the pump 16 which is in turn controlled by its cam 160.

To define the duration of the valve opening, a plurality of spillportvents 69 are provided in the upper flange 53 of the barrel 52. When ashoulder 70 of the valve plunger 62 reaches the spillports 69, thepressurized fluid in the chamber 66 is immediately spilled or ventedthrough the spillports 69 and their connected annular passageway 71 toan oil return passageway 72 and thence into the oil return line 24. Theannular passageway 71 is formed in the cap 50 and is disposed forcommunication with all the spillports 69 and the fluid return passageway72, as best seen in FIGS. 3 and 5. When the spillports 69 are open torelieve the pressure in the cylinder 66, hydraulic fluid is returned tothe fluid tank 13 and the compression spring 40 immediately returns theplunger 62, valve stem 39, and valve head 34 to the closed position.

As discussed above, the adjustment sleeve 48 is threadably connected tothe upper housing 38. Rotation of the sleeve 48 thus moves the sleeve 48axially with respect to the plunger 62 which is moved axially only byoil pressure as described. Axial movement of the sleeve 48 also movesthe axial position of the cap 50, barrel 52, and mounting sleeve 54.With downward movement of the adjustment sleeve 48, the collar 49assures corresponding downward movement of the cap 50, barrel 52, andmounting sleeve 54. With upward movement of the sleeve 48, thecompression springs 57 assure that the cap 50 again follows the collar49 and correspondingly moves upward. This axial movement of the cap 50and barrel 52 with respect to the plunger 62 varies the relative axialposition of the relief spillports 69 to vary the point at which theplunger shoulder 70 will clear the relief spillports 69 to vent thesystem. Thus the duration of valve opening and consequently the size ofthe fuel charge injected through the valve 33 into the cylinder 12 canbe controlled by rotation of the screw threaded adjustment sleeve 48.Rotation of the sleeve 48 to move it and the spillports 69 in a downwarddirection will lengthen the stroke of the valve plunger 62 toincreasethe volume of the fuel charge. FIG. 5 shows the sleeve 48 andspillports 69 in nearly lowermost, maximum stroke position, while FIG. 3indicates a higher, shorter stroke position.

A set screw 75 is provided in the adjustment sleeve 48 for locking itagainst rotation when the charge size has been satisfactorily adjusted.

FIG. 3 indicates the relative positions of the cap 50, bolts 55, guidepins 56, annular fluid passageway 71, spillports 69, slave cylinder 67,and valve plunger 62. Spillport passageways 76 link the annular fluidpassageway 71 with the spillports 69.

Referring now to FIG. 4, the spill-port 69 shape is square orrectangular rather than circular. This external or radially outer endcan be circular but the inner face next to the plunger is preferablysquare or rectangular. This rectangular configuration'facilitates easierand more accurate adjustment of the valve plunger stroke by providing asubstantially linear variation of relief port area exposure to thehydraulic fluid. Thus a given increment of rotation of the sleeve 48will have a corresponding given axial movement of the spillports 69,with a corresponding given change in the fuel charge size, over theentire range of adjustment. This means that the external sleeve can becalibrated in a linear manner and also facilitates the matching ofadjustments from cylinder to cylinder.

The above described preferred embodiment provides a fuel injectioncontrol system easily and readily adjustable from the valve end of thesystem. This adjustability directly at the valve, along with thespecifically described arrangement and cooperation of the variouscomponents, facilitates the attainment of a high degree of accuracy inthe adjustment of the duration of the intake valve stroke, which isparticularly advantageous in balancing combustion in the cylinders of amultiple cylinder internal combustion engine. For example, accuratebalancing of the loads carried by a two cycle engine can be easilyaccomplished by monitoring the exhaust temperatures from each. If thetemperatures are not in substantial balance, a simple adjustment toeither cylinder can be made using the valve adjustment described torestore load balance.

Various other embodiments and alterations to the preferred embodimentwill be apparent to those skilled in the art and may be made withoutdeparting from the spirit and scope of the following claims.

I claim:

1. A hydraulic fuel valve control system including a driven hydraulicpump connected in a closed hydraulic circuit to a hydraulically operablevalve assemblyextending into a combustion chamber to intermittentlyadmit a fuel to the combustion chamber, said valve assembly including ahousing with a valve disposed therein in communication with a source offuel and said combustion chamber, means for biasing said valve in closedposition, an axially movable plunger positioned to open said valve whenmoved downwardly, ,said plunger disposed within a sleeve which includesspillport relief vents, hydraulic fluid supply and return linesconnecting said pump with a fluid chamber above said plunger and withsaid relief vents, respectively, an axially translatable cap extendingabove and secured to said sleeve for axial movement therewith, and anexternal adjustment sleeve peripherally engaging said cap and threadablyconnected to said housing, whereby, when said plunger is moveddownwardly by hydraulic pressure from said pump, said valve will openand remain open until said spillports are uncovered by said plunger torelease pressure thereupon, and whereby incremental rotation of saidadjustment sleeve will adjust the axial position of said sleeve and itsspillports to vary the duration of said valve is held open by saidplunger.

2. The apparatus of claim 1 wherein said cap includes a lower flange andsaid adjustment sleeve includes an upper hold-down collar engaging saidlower flange, with at least one compression spring operably connected tosaid housingand to said cap biasing said cap from said housing.

3. In an internal combustion engine, a fuel injection control systemcomprising a source of hydraulic fluid including a plunger pumpactuatedby a cam operably connected to such engine and effective to supply fluidpressure pulses in timed relation to engine speed;

' a valve assembly operably connected to saidplunger pump by a fluidsupply and a fluid return line, said valve assembly extending into acombustion cylinder of the engine, said valve assembly comprisingreciprocate with said. valve, means for biasing said a valve and valveplunger upward toward a closed position, a barrel circumjacent a portionof said plunger defining a cylinder about said plunger, said barrelincluding a relief vent in communication with said plunger and saidcylinder, means for establishing fluid communication between said fluidsupply line and said plunger and cylinder, means for returning hydraulicfluid from said relief vent to said fluid return line, and relief ventadjustment means comprising a slidable connection between barrel barrleand the upper end of said housing, an adjustment sleeve threadablyconnected to the upper end of said housing and axially movable toward oraway from said housing in response to rotation about said housing and.means for operably connecting said barrel to said sleeve for axialmovement therewith.

i. The apparatus of claim 3 wherein said barrel connecting meanscomprises a cap connected to said barrel, said cap having an outwardlyextending lower circular flange, said adjustment sleeve having aninwardly extending collar engaging said flange from above, a compressionspring mounted between said housing and said cap biasing said housingand said cap apart, and means for preventing rotation of said cap withrespect to said housing.

5. A valve assembly, comprising:

a housing including a valve seat and a fuel chamber for connection to afuel source; I

a valve head adjacent said valve seat adapted to reciprocate betweenopen and closed positions, said valve head being connected to a valvestem extendingupward in said housing;

a compression spring connected to said valve stem biasing said valvestem and valve head toward an upward, closed position;

a valve plunger abutting said valve stem and extending further axiallyupward;

a cylinder circumjacent the upper end of said valve plunger including aplurality of relief spillports, said cylinder being axially translatablewith respect to said housing, said valve plunger being axiallyreciprocal within said cylinder;

means for connecting a source of pressurized hydraulic fluid incommunication with the upper end of said valve plunger;

, means for connecting said relief spillports to a fluid return line;and

an adjustment sleeve threadably connected to the upper end of saidhousing and axially movable toward or away from said housing in responseto rotation about said housing, and means for operably connecting saidcylinder to said sleeve for axial movement therewith,

whereby, the axial position of said relief spillports may be externallyadjusted by rotation of said adjustment sleeve.

6. A valve assembly, comprising:

a housing including a valve seat and a fuel chamber for connection to afuel source;

a valve head adjacent said valve seat adapted to reciprocate betweenopen and closed positions, said valve head being connected to a valvestem extending axially'upward in said housing;

a compression spring connected to said valve stem biasing said valvestem and valve head toward an upward, closed position;

a valve plunger abutting said valve stem and extending further axiallyupward;

a cylinder circumjacent the upper end of said valve plunger including aplurality of relief spillports, said cylinder being axially movable withrespect to said housing and defining a length of axial travel from alower maximum valve stroke position to an upper minimum valve strokeposition, said valve 7 plunger being axially reciprocable within saidcylinder;

means for connecting a source of pressurized hydraulic fluid incommunication with the upper end of said valve plunger;

means for connecting said relief spillports to a fluid return line; and

means for externally adjusting the position of said cylinder andspillports within said length of axial travel.

7. A valve assembly according to claim 6 wherein said relief spillportsare rectangular.

8. In an internal combustion engine, a fuel injection control systemcomprising a source of hydraulic fluid including a plunger pump actuatedby a cam operably connected to such engine and effective to supply fluidpressure pulses in timed relation to engine speed;

a valve assembly operably connected to said plunger pump by a fluidsupply and a fluid return line, said valve assembly extending into acombustion cylin-' der of the engine, said valve assembly comprising ahousing having a chamber in communication with a source of fuel, a valvein said chamber extending into the cylinder, an axially extendingrecipr'ocable valve plunger within said housing extending upward out ofsaid housing and positioned to axially reciprocate with said valve,means for biasing said valve and valve plunger upward toward a closedposition, a barrel circumjacent a portion of said plunger defining acylinder about said plunger, said barrel including a relief vent incommunication with said plunger and said cylinder, said barrel andrelief vent being axially movable with respect to said housing anddefining a length of axial travel from the lower maximum valve strokeposition to an upper minimum valve stroke position, means forestablishing fluid communication between said fluid supply line and saidplunger and cylinder, means for returning hydraulic fluid from saidrelief vent to said fluid return line, and external means for adjustingthe axial position of said barrel and relief vent, whereby the stroke ofsaid plunger is externally adjustable.

9. A hydraulic fuel valve control system including a driven hydraulicpump connected in a closed hydraulic circuit to a'hydraulically operablevalve assembly extending into a combustion chamber to intermittentlyadmit a fuel to the combustion chamber, said valve assembly including ahousing with a valve disposed therein in communication with a source offuel and said combustion chamber, means for biasing said valve in closedposition, an axially movable plunger positioned to open said valve whenmoved downwardly, said plunger disposed within a sleeve which includesaxially aligned rectangular spillport relief vents, hydraulic fluidsupply and return lines connecting said pump with a fluid chamber abovesaid plunger and with said relief vents, respectively, and means foraxially adjusting the position of said sleeve and its spillports withrespect to said housing whereby, when said plunger is moved dowardly byhydraulic pressure from said pump, said valve will open and remain openuntil said spillports are uncovered by said plunger to release pressurethere: upon, and whereby adjustment of the axial position of saidspillports will vary the duration that said valve is held open by saidplunger.

10. A hydraulic fuel valve control system for multiple cylinder internalcombustion engines comprising, at least one driven hydraulic pumpoperably connected to a hydraulic supply line to provide an intermittentseries of pressure pulses in timed relation to engine speed, ahydraulically operated valve assembly associated with each of saidcylinders with each of said valves con-' nected to a hydraulic supplyline such that such pressure pulses are applied thereto with desiredtiming to open said valve; each of said valves comprising a valve headand seat interconnected between a source of fuel and the combustionchamber of that cylinder, means for biasing said valve head in closedposition, a valve plunger extending axially upwardly away from saidvalve and having its upper end terminating in a hydraulic pressurechamber connected to said supply line, a sleeve including spillportsdisposed circumjacent said plunger with said spillports positionedadjacent said pressure chamber whereby movement of said upper end ofsaid plunger below said spillports is effective to vent said chamber,said sleeve being axially movable with respect to said valve plunger anddefining a length of axial travel from a lower maximum valve strokeposition to an upper minimum valve stroke position, and external meansfor varying the axial position of said sleeve within said length ofaxial travel whereby the duration and stroke of the valve opening andthe volume of fuel in each cylinder can be adjusted externally ofCERTIFICATE OF toRREcTmN Patent No. 3,872,844 i Dated March 25, 1975UNITED STATES PATENT OFFICE Inventor(g) Alfred C. Gates It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In the claims:

Column 6, line 2; this line should read:

--said barrel and the upper end of said housing, an-- Signed and sealedthis 20th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C, MASON Commissioner of Patents Attesting Officerand Trademarks FORM PCMOSO uscoMM-Dc 60376-P69 L5. GOVERNMENT PRINTINGOFFICE 7 I959 0-355-334.

1. A hydraulic fuel valve control system including a driven hydraulicpump connected in a closed hydraulic circuit to a hydraulically operablevalve assembly extending into a combustion chamber to Intermittentlyadmit a fuel to the combustion chamber, said valve assembly including ahousing with a valve disposed therein in communication with a source offuel and said combustion chamber, means for biasing said valve in closedposition, an axially movable plunger positioned to open said valve whenmoved downwardly, said plunger disposed within a sleeve which includesspillport relief vents, hydraulic fluid supply and return linesconnecting said pump with a fluid chamber above said plunger and withsaid relief vents, respectively, an axially translatable cap extendingabove and secured to said sleeve for axial movement therewith, and anexternal adjustment sleeve peripherally engaging said cap and threadablyconnected to said housing, whereby, when said plunger is moveddownwardly by hydraulic pressure from said pump, said valve will openand remain open until said spillports are uncovered by said plunger torelease pressure thereupon, and whereby incremental rotation of saidadjustment sleeve will adjust the axial position of said sleeve and itsspillports to vary the duration of said valve is held open by saidplunger.
 2. The apparatus of claim 1 wherein said cap includes a lowerflange and said adjustment sleeve includes an upper hold-down collarengaging said lower flange, with at least one compression springoperably connected to said housing and to said cap biasing said cap fromsaid housing.
 3. In an internal combustion engine, a fuel injectioncontrol system comprising a source of hydraulic fluid including aplunger pump actuated by a cam operably connected to such engine andeffective to supply fluid pressure pulses in timed relation to enginespeed; a valve assembly operably connected to said plunger pump by afluid supply and a fluid return line, said valve assembly extending intoa combustion cylinder of the engine, said valve assembly comprising ahousing having a chamber in communication with a source of fuel, a valvein said chamber extending into the cylinder, an axially extendingreciprocable valve plunger within said housing extending upward out ofsaid housing and positioned to axially reciprocate with said valve,means for biasing said valve and valve plunger upward toward a closedposition, a barrel circumjacent a portion of said plunger defining acylinder about said plunger, said barrel including a relief vent incommunication with said plunger and said cylinder, means forestablishing fluid communication between said fluid supply line and saidplunger and cylinder, means for returning hydraulic fluid from saidrelief vent to said fluid return line, and relief vent adjustment meanscomprising a slidable connection between barrel barrle and the upper endof said housing, an adjustment sleeve threadably connected to the upperend of said housing and axially movable toward or away from said housingin response to rotation about said housing and means for operablyconnecting said barrel to said sleeve for axial movement therewith. 4.The apparatus of claim 3 wherein said barrel connecting means comprisesa cap connected to said barrel, said cap having an outwardly extendinglower circular flange, said adjustment sleeve having an inwardlyextending collar engaging said flange from above, a compression springmounted between said housing and said cap biasing said housing and saidcap apart, and means for preventing rotation of said cap with respect tosaid housing.
 5. A valve assembly, comprising: a housing including avalve seat and a fuel chamber for connection to a fuel source; a valvehead adjacent said valve seat adapted to reciprocate between open andclosed positions, said valve head being connected to a valve stemextending upward in said housing; a compression spring connected to saidvalve stem biasing said valve stem and valve head toward an upward,closed position; a valve plunger abutting said valve stem and extendingfurther axially upward; a cylinder circumjacent the upper end of saidvalve plungeR including a plurality of relief spillports, said cylinderbeing axially translatable with respect to said housing, said valveplunger being axially reciprocal within said cylinder; means forconnecting a source of pressurized hydraulic fluid in communication withthe upper end of said valve plunger; means for connecting said reliefspillports to a fluid return line; and an adjustment sleeve threadablyconnected to the upper end of said housing and axially movable toward oraway from said housing in response to rotation about said housing, andmeans for operably connecting said cylinder to said sleeve for axialmovement therewith, whereby, the axial position of said reliefspillports may be externally adjusted by rotation of said adjustmentsleeve.
 6. A valve assembly, comprising: a housing including a valveseat and a fuel chamber for connection to a fuel source; a valve headadjacent said valve seat adapted to reciprocate between open and closedpositions, said valve head being connected to a valve stem extendingaxially upward in said housing; a compression spring connected to saidvalve stem biasing said valve stem and valve head toward an upward,closed position; a valve plunger abutting said valve stem and extendingfurther axially upward; a cylinder circumjacent the upper end of saidvalve plunger including a plurality of relief spillports, said cylinderbeing axially movable with respect to said housing and defining a lengthof axial travel from a lower maximum valve stroke position to an upperminimum valve stroke position, said valve plunger being axiallyreciprocable within said cylinder; means for connecting a source ofpressurized hydraulic fluid in communication with the upper end of saidvalve plunger; means for connecting said relief spillports to a fluidreturn line; and means for externally adjusting the position of saidcylinder and spillports within said length of axial travel.
 7. A valveassembly according to claim 6 wherein said relief spillports arerectangular.
 8. In an internal combustion engine, a fuel injectioncontrol system comprising a source of hydraulic fluid including aplunger pump actuated by a cam operably connected to such engine andeffective to supply fluid pressure pulses in timed relation to enginespeed; a valve assembly operably connected to said plunger pump by afluid supply and a fluid return line, said valve assembly extending intoa combustion cylinder of the engine, said valve assembly comprising ahousing having a chamber in communication with a source of fuel, a valvein said chamber extending into the cylinder, an axially extendingreciprocable valve plunger within said housing extending upward out ofsaid housing and positioned to axially reciprocate with said valve,means for biasing said valve and valve plunger upward toward a closedposition, a barrel circumjacent a portion of said plunger defining acylinder about said plunger, said barrel including a relief vent incommunication with said plunger and said cylinder, said barrel andrelief vent being axially movable with respect to said housing anddefining a length of axial travel from the lower maximum valve strokeposition to an upper minimum valve stroke position, means forestablishing fluid communication between said fluid supply line and saidplunger and cylinder, means for returning hydraulic fluid from saidrelief vent to said fluid return line, and external means for adjustingthe axial position of said barrel and relief vent, whereby the stroke ofsaid plunger is externally adjustable.
 9. A hydraulic fuel valve controlsystem including a driven hydraulic pump connected in a closed hydrauliccircuit to a hydraulically operable valve assembly extending into acombustion chamber to intermittently admit a fuel to the combustionchamber, said valve assembly including a housing with a valve disposedtherein in communication with a source of fuel and said combustionchamber, means for biasing saiD valve in closed position, an axiallymovable plunger positioned to open said valve when moved downwardly,said plunger disposed within a sleeve which includes axially alignedrectangular spillport relief vents, hydraulic fluid supply and returnlines connecting said pump with a fluid chamber above said plunger andwith said relief vents, respectively, and means for axially adjustingthe position of said sleeve and its spillports with respect to saidhousing whereby, when said plunger is moved dowardly by hydraulicpressure from said pump, said valve will open and remain open until saidspillports are uncovered by said plunger to release pressure thereupon,and whereby adjustment of the axial position of said spillports willvary the duration that said valve is held open by said plunger.
 10. Ahydraulic fuel valve control system for multiple cylinder internalcombustion engines comprising, at least one driven hydraulic pumpoperably connected to a hydraulic supply line to provide an intermittentseries of pressure pulses in timed relation to engine speed, ahydraulically operated valve assembly associated with each of saidcylinders with each of said valves connected to a hydraulic supply linesuch that such pressure pulses are applied thereto with desired timingto open said valve; each of said valves comprising a valve head and seatinterconnected between a source of fuel and the combustion chamber ofthat cylinder, means for biasing said valve head in closed position, avalve plunger extending axially upwardly away from said valve and havingits upper end terminating in a hydraulic pressure chamber connected tosaid supply line, a sleeve including spillports disposed circumjacentsaid plunger with said spillports positioned adjacent said pressurechamber whereby movement of said upper end of said plunger below saidspillports is effective to vent said chamber, said sleeve being axiallymovable with respect to said valve plunger and defining a length ofaxial travel from a lower maximum valve stroke position to an upperminimum valve stroke position, and external means for varying the axialposition of said sleeve within said length of axial travel whereby theduration and stroke of the valve opening and the volume of fuel in eachcylinder can be adjusted externally of the respective valve assembly.